1 . Field of the Invention
The invention relates to the field of display technology, and particularly to an array substrate and a display device.
2 . Description of Related Art
A liquid crystal display (LCD) is a commonly used electronic device, and because of its low power consumption, small size, light weight and other characteristics, it is quite popular for users. In a thin film transistor liquid crystal display (TFT-LCD) employing a vertical alignment technology, a pixel generally is demarcated/divided into a main area and a sub area, and a pixel voltage applied onto the sub area is lower than a pixel voltage applied onto the main area so as to improve the large viewing angle color shift. Under general circumstances, an array substrate disposed with a thin film transistor of main area and a thin film transistor of sub area is disposed with a pull-down capacitor. The pull-down capacitor is cooperative with the thin film transistor of the sub area to share a part of charges on the thin film transistor of the sub area, so as to make the pixel voltage of the sub area to be decreased to an appropriate proportion. The pull-down capacitor adopts a MII structure, and a structure of the pull-down capacitor with the MII structure generally includes a metal layer, a first insulating layer (e.g., G-SiNx), a second insulating layer (PA-SiNx) and a transparent conductive layer. Thus it can be seen that, the topmost layer of the pull-down capacitor with the MII structure generally is the transparent conductive layer, such as indium tin oxides (ITO). The topmost layer of the thin film transistor of the sub area also is a transparent conductive layer (may be a pixel electrode), the transparent conductive layer as the topmost layer of the thin film transistor of the sub area and the transparent conductive layer as the topmost layer of the pull-down capacitor with the MII structure are located on a same layer, and the two transparent conductive layers have a small gap therebetween. In a fabricating process of the array substrate, such as etching or developing process, it is easy to produce residual transparent conductive layer, resulting in short circuit occurred between the transparent conductive layer as the topmost layer of the thin film transistor of the sub area (Sub TFT) and the transparent conductive layer as the topmost layer of the pull-down capacitor with the MII structure, the pull-down capacitor could not normally pull down the pixel voltage of the sub area, the pixel would produce a small bright spot and display quality of the display device is affected consequently. Please refer to FIG. 1 and FIG. 2, FIG. 1 is a schematic view showing short circuit occurred between a transparent conductive layer as the topmost layer of a thin film transistor of sub area and a transparent conductive layer as the topmost layer of a pull-down capacitor in the prior art, and FIG. 2 is a schematic view showing a small bright spot produced/displayed on a display device in the prior art. As illustrated in FIG. 1 and FIG. 2, the produced small bright spot caused by the short circuit occurred between the transparent conductive layer as the topmost layer of the thin film transistor of sub area and the transparent conductive layer as the topmost layer of the pull-down capacitor is denoted by SP, and the pull-down capacitor is represented by C.